<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>websocket</title>
    <script src="http://localhost:9090/socket.io/socket.io.js"></script>
    <script>
        let sock = io.connect('ws://localhost:9090/');
        document.onclick = function () {  
            sock.emit('a',1,2);
        }
    </script>
</head>
<body>
    

</body>
</html>